If you said the above italicized statment to a brick wall and a pro-drug Libertarian on FR, which one would actually listen.
My bet is on the brick wall.
I guess, but so what? There are just too many things wrong with the position you've articulated.
First is that by dispensing drugs through the medical establishment, you set up a situation where cheating is rewarded and honesty is punished. Suppose there are two people both of whom want some oxycontin. Individual A goes to the doctor, tells the truth, and is denied. Individual B lies to the doctor and gets a prescription.
Second, your inconsistency promotes disrepect for law. "Dad, can I have one of your oxycontin?" No. Why not? Because they're illegal. Why is it illegal? Because you could become addicted and ruin your life, never accomplish your dreams, become a burden on society. Couldn't I also ruin my life, fail to accomplish my dreams, and become a burden on society if I stop daily ablutions, stink so no one will hire me, have my teeth rot and health deteriorate so that I become a burden on society? Yes. So how come there's no law that I bathe?
Finally the restrictions on what individuals can ingest in the privacy of their own homes goes to the very core of liberty. Liberty is not the search for what is safe and productive, although both are its by-products. And even if it were, how do we know, apriori what is safe and productive? It is the very exercise of liberty that provides such knowledge. Some provide the information some in a negative way (Evil Kenival), and some in a positive way (Jonas Salk) and even Salk had trials where children died.
Apparently, Rush was able to perform at a very high level for years while "medicated" at a level we were all told would render him unconscious or worse. Apparently we were told wrong. We all know more now than we did before. We also know we got 3 or more years of entertainment and enlightenment from from his show that we would not have gotten had he felt the full wrath of prohibitionists.